Precipitated calcium carbonate
AssigneeECC International Limited
InventorsIan S. Bleakley, Thomas R. Jones
Life of this patent
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Abstract
The calcium carbonate is prepared by: (a) slaking quicklime in an aqueous medium; (b) carbonating and neutralising the suspension of slaked lime formed in step (a) using a gas comprising carbon dioxide; and (c) separating the precipitated calcium carbonate formed in step (b) from the aqueous medium in which it is suspended. There is added 0.1% to 2% by weight, based on the weight of dry calcium oxide, of a reagent having one or more active hydrogen atoms (or a salt thereof), to the aqueous medium in which the quicklime is slaked in step (a).
Claims13
In a process of preparing calcium carbonate, which comprises the following steps:
- (a) slaking quicklime in an aqueous medium;
- (b) carbonating the suspension of slaked lime formed in step (a) by passing therethrough sufficient of a gas comprising carbon dioxide to cause the pH of the suspension to fall to substantially neutral;
- and
- (c) separating the precipitated calcium carbonate formed in step (b) from the aqueous medium in which it is suspended;
- wherein the improvement comprises adding a reagent comprising a polyhydric alcohol or a polyhydric phenol to the aqueous medium in which the quicklime is slaked in step (a).
Dependencies are inferred from the claim text.